A personal air sampling pump assembly includes a motor having a reciprocating piston for operating a diaphragm assembly. The diaphragm includes a valve head including a fluid inlet and a fluid outlet and a fluid chamber defining a fluid path between the inlet and outlet. A first and second diaphragm sealing engaging the valve head and enclosing the fluid chamber. The first diaphragm includes a piston diaphragm membrane portion coupled to the piston for reciprocating with the piston and wherein reciprocation of the piston causes a change in air pressure within the fluid chamber to cause air to move from the fluid inlet toward the fluid outlet. Both the first and second diaphragms include a damper membrane portion, which cooperate to reduce an amplitude of pulsation in the airflow at the fluid inlet and fluid outlet.

A fracturing apparatus, a control method of the fracturing apparatus and a fracturing system. The fracturing apparatus includes a plunger pump, a prime mover, a clutch and a clutch hydraulic system. The prime mover includes a power output shaft, and the clutch includes a first connection portion, a second connection portion and a clutch portion between the first connection portion and the second connection portion. The power end of the plunger pump includes a power input shaft, the first connection portion is connected with the power input shaft, the second connection portion is connected with the power output shaft of the prime mover, and the clutch hydraulic system is configured to provide hydraulic oil to the clutch. The fracturing apparatus further includes a first pressure sensor arranged in the clutch hydraulic system and configured to detect the hydraulic pressure of the clutch hydraulic system.

An apparatus for damping pressure pulsation for a compressor of a gaseous fluid in a refrigerant circuit including a housing with an inlet opening and at least one first outlet opening and a piston element movable in an axial direction within a volume enclosed by the housing and supported on the housing in a beared manner via a spring element, wherein the piston element respectively controls a flow cross section of the inlet opening and the first outlet opening, wherein the piston element and the housing have at least one first sealing surface and a second sealing surface. The first sealing surfaces form a first seat and the second sealing surfaces form a second seat, wherein between the seats, one chamber enclosed by the housing and the piston element for expanding the fluid when flowing into the chamber and/or at least one second outlet opening in the housing is formed.

A miniature vacuum pump includes a collection and exhaust chamber, a driving motor, and a vacuum breaking assembly including an inlet hole extending through a bottom wall of the collection and exhaust chamber, a pressure plate movably fitting about the output shaft located in the collection and exhaust chamber and flexibly covering the inlet hole, a rotation member coaxially and fixedly mounted to the output shaft and located at a side of the pressure plate opposite to the bottom wall and forming a rotation frame, and a centrifugal swing rod rotatably mounted to the rotation frame through a rotation shaft perpendicular to the output shaft. A center of gravity of the centrifugal swing rod is set at an end away from the rotation member, and an opposite end of the centrifugal swing rod is bent and extended to form a pressing portion for abutting against the pressure plate.

A pump assembly includes a pneumatic pump with a pump body having a discharge passage. The pump is operable to discharge compressed air through the discharge passage. The pump assembly also includes a cap adjacent the pump body and at least partially enclosing a first volume in communication with the discharge passage, and a casing at least partially surrounding the pump. The pump assembly further includes a second volume defined between the casing and the cap, the second volume in fluid communication with the first volume via an opening in the cap, and a casing outlet in fluid communication with the second volume. The pump assembly is configured such that the compressed air flows through the first volume and the second volume before being discharged from the casing through the casing outlet.

A miniature vacuum pump includes a collection and exhaust chamber, a driving motor, and a vacuum breaking assembly including an inlet hole extending through a bottom wall of the collection and exhaust chamber, a pressure plate movably fitting about the output shaft located in the collection and exhaust chamber and flexibly covering the inlet hole, a rotation member coaxially and fixedly mounted to the output shaft and located at a side of the pressure plate opposite to the bottom wall and forming a rotation frame, and a centrifugal swing rod rotatably mounted to the rotation frame through a rotation shaft perpendicular to the output shaft. A center of gravity of the centrifugal swing rod is set at an end away from the rotation member, and an opposite end of the centrifugal swing rod is bent and extended to form a pressing portion for abutting against the pressure plate.

The present disclosure relates to a piston compressor, comprising a crankcase, at least two exhaust mufflers, a valve plate assembly, a cylinder head, a connecting pipe and an exhaust pipe. The cylinder head comprises a cylinder head high-pressure chamber, the crankcase comprises a crankcase exhaust passage, and the crankcase exhaust passage is connected to the cylinder head high-pressure chamber of the cylinder head through a one-way exhaust hole in the valve plate assembly. The crankcase and the valve plate assembly each comprise at least two exhaust holes respectively associated with the at least two exhaust mufflers, and the cylinder head high-pressure chamber of the cylinder head is connected to the at least two exhaust mufflers through the corresponding exhaust holes in the crankcase and the valve plate assembly. The connecting pipe connects the at least two exhaust mufflers, and the exhaust pipe is connected to any one of the at least two exhaust mufflers, thereby forming at least two gas discharge paths. In addition, the present disclosure further relates to a mobile refrigerator comprising the piston compressor.

An air sampling pump includes a reciprocating piston for operating a diaphragm assembly. The diaphragm includes a valve head including a fluid inlet and a fluid outlet and a fluid chamber defining a fluid path between the inlet and outlet. A diaphragm sealing engages the valve head and encloses the fluid chamber. The diaphragm includes a piston diaphragm membrane portion coupled to the piston for reciprocating with the piston and reciprocation of the piston causes a change in air pressure within the fluid chamber to cause air to move from the fluid inlet toward the fluid outlet. The diaphragm includes a damper membrane portion, which cooperate to reduce an amplitude of pulsation in the airflow at the fluid inlet and fluid outlet.